An electrosurgical generator for supplying power, including an inverter for high voltage, which is led to an output to the connector of an electrosurgical instrument, a measurement system with at least one measurement monitor for a physical parameter at the output or at the electrosurgical instrument, and an operation controller which controls the inverter on the basis of at least one predefined operating sequence. The measurement monitor for the physical parameter is switchable between a plurality of different configurations which differ in the measurement range. The operation controller interacts with the measurement system so one of the different configurations of the measurement monitor is switched in each case, under control by the operating sequence. By switching the configuration, the suitable measurement range is always set during operation. Apparently contrariwise requirements in relation to a reliable measurement even at high amplitudes are linked with great measurement accuracy even at low amplitudes.

Transducer-based systems can be configured to display a graphical representation of a transducer-based device, the graphical representation including graphical elements corresponding to transducers of the transducer-based device, and also including between graphical elements respectively associated with a set of the transducers and respectively associated with a region of space between the transducers of the transducer-based device. Selection of graphical elements and/or between graphical elements can cause activation of the set of transducers associated with the selected elements. Selection of a plurality of graphical elements and/or between graphical elements can cause visual display of a corresponding activation path in the graphical representation. Visual characteristics of graphical elements and between graphical elements can change based on an activation-status of the corresponding transducers. Activation requests for a set of transducers can be denied if it is determined that a transducer in the set of transducers is unacceptable for activation.

An elongate medical device shaft may comprise an elongate body and an annular electrode disposed on the elongate body. The annular electrode may define a longitudinal axis and have an outer diameter. The outer diameter may be greater at an axial center of the electrode than at an axial end of the electrode. Additionally or alternatively, the elongate body may comprise three longitudinal sections having three wall thicknesses. The middle wall thickness may be less than the proximal and distal wall thicknesses and the distal wall thickness may be less than the proximal wall thickness. Additionally or alternatively, the shaft may comprise an inner cylindrical structure and an outer tube. The outer tube may comprise a first radial layer and a second radial layer that is radially-outward of the first radial layer, the first radial layer, second radial layer, and inner structure having different stiffnesses.

Various aspects of a generator, ultrasonic device, and method for estimating and controlling a state of an end effector of an ultrasonic device are disclosed. The ultrasonic device includes an electromechanical ultrasonic system defined by a predetermined resonant frequency, including an ultrasonic transducer coupled to an ultrasonic blade. A control circuit measures a complex impedance of an ultrasonic transducer, wherein the complex impedance as defined as

[00001]$Z_g\left(t\right)=\frac{V_g\left(t\right)}{I_g\left(t\right)};$

The control circuit receives a complex impedance measurement data point and compares the complex impedance measurement data point to a data point in a reference complex impedance characteristic pattern. The control circuit then classifies the complex impedance measurement data point based on a result of the comparison analysis and assigns a state or condition of the end effector based on the result of the comparison analysis. The control circuit estimates the state of the end effector of the ultrasonic device and controls the state of the end effector of the ultrasonic device based on the estimated state.

In an energy control device, a processor detects a gradual decrease start time at which the electric characteristic value in relation to electric energy output to an ultrasonic transducer starts a gradual decrease after a gradual increase. The processor calculates a difference value by subtracting the electric characteristic value from a peak value at gradual decrease start time and calculates an integrated value of the difference value from the gradual decrease start time. The processor executes, based on a fact that the integrated value become greater than a predetermined threshold, at least one of causing to stop or reduce the output of the electric energy to the ultrasonic transducer, and notifying that the integrated value become greater than the predetermined threshold.

Examples described herein may include medical devices and electrosurgical generators with resonant isolated transformers to perform filtering and gain functions. An example electrosurgical generator includes a radio frequency (RF) inverter stage configured to receive an input signal and, in response to control feedback signals, to provide an output signal that provides power to a load. The RF inverter stage includes a resonant isolated transformer configured to receive the input signal and to provide gain and filtering adjustments to the input signal to provide the output signal.

An electrosurgical generator includes a processor and a memory storing instructions executable by the processor. The instructions when executed, cause the generator to provide an indicated treatment energy to the instrument, where the indicated treatment energy is set by a user and having a corresponding current limit, receive signals from the instrument over time relating to a load impedance between the active electrode and the return electrode of the instrument, determine based on the signals that the active electrode and the return electrode are currently shorted together, and prior to the short, the instrument was grasping tissue between the active electrode and the return electrode, and based on the determination, reduce a current limit of treatment energy being provided to the instrument to below the corresponding current limit.

Transducer-based systems and methods may be configured to display a graphical representation of a transducer-based device, the graphical representation including graphical elements corresponding to transducers of the transducer-based device, and also including between graphical elements respectively associated with a set of the transducers and respectively associated with a region of space between the transducers of the transducer-based device. Selection of graphical elements and/or between graphical elements can cause activation of the set of transducers associated with the selected elements. Transducer activation characteristics, such as initiation time, activation duration, activation sequence, and energy delivery characteristics, can vary based on numerous factors. Visual characteristics of graphical elements and between graphical elements can change based on an activation-status of the corresponding transducers. Activation requests for a set of transducers can be denied if it is determined that a transducer in the set of transducers is unacceptable for activation.

A method is provided to control delivery of heat to biological tissue comprising: imparting an RF electrical signal to the biological tissue electrically coupled between a first electrode and the second electrode; measuring frequency content of the RF electrical signal between the first electrode and the second electrode; and adjusting the RF electrical signal based upon the measured frequency content of the RF electrical signal.

An electrosurgical controller and related methods. At least some of the illustrative embodiments are methods including: placing a distal end of an electrosurgical wand in operational relationship with biological tissue; delivering energy to an active electrode of the electrosurgical wand. During delivering energy, the method may comprise: measuring a value indicative of flow of the energy to the active electrode; summing, over a first predetermined window of time, to create a first value indicative of energy provided to the active electrode; summing, over a second predetermined window of time, to create a second value indicative of energy provided to the active electrode. The method may further comprise: ceasing delivering energy responsive to the first value meeting or exceeding a predetermined value; and ceasing delivering energy responsive to the second value meeting or exceeding a threshold value.